CVE-2025-4355: Critical Heap-Based Buffer Overflow Vulnerability in Tenda DAP-1520

Overview

The vulnerability CVE-2025-4355 is a critical security flaw discovered in the Tenda DAP-1520, a popular networking device. The vulnerability resides within the ‘set_ws_action’ function of the ‘/dws/api/’ file, leading to a heap-based buffer overflow. This vulnerability is especially serious as it allows a potential attacker to initiate the attack remotely, which could lead to a full system compromise or data leakage. Given the widespread use of Tenda DAP-1520, this vulnerability could impact a large number of systems and networks globally.

Vulnerability Summary

CVE ID: CVE-2025-4355
Severity: Critical (8.8 CVSS Score)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage

Affected Products

Product | Affected Versions

Tenda DAP-1520 | 1.10B04_BETA02

How the Exploit Works

The vulnerability exploits the ‘set_ws_action’ function of the ‘/dws/api/’ file. The function does not properly manage the memory space allocated for user-supplied data, leading to a heap-based buffer overflow condition. An attacker can send a specially crafted payload that overflows the buffer, which can result in arbitrary code execution or even a system crash.

Conceptual Example Code

This is a conceptual example of how an attacker might exploit this vulnerability. In this scenario, the attacker sends a crafted HTTP POST request to the vulnerable endpoint:

POST /dws/api/set_ws_action HTTP/1.1
Host: vulnerable-device-ip
Content-Type: application/json
{ "malicious_payload": "A"*5000 }

In this example, the ‘malicious_payload’ is a string of ‘A’ characters that is much larger than what the buffer can handle. This input will cause the buffer to overflow, leading to potential execution of arbitrary code or crashing the system.

Mitigation

To protect your systems from this vulnerability, it is recommended to apply the vendor-provided patch immediately. If the patch cannot be applied immediately, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) could provide temporary mitigation. However, these are not long-term solutions and can only limit the potential impact of an exploit. The best protection against this vulnerability is to update your Tenda DAP-1520 to a version that has fixed this issue.